Hadith
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي أُمَامَةَ بْنِ سَهْلٍ، قَالَ مَرِضَتِ امْرَأَةٌ مِنْ أَهْلِ الْعَوَالِي وَكَانَ النَّبِيُّ صلى الله عليه وسلم أَحْسَنَ شَىْءٍ عِيَادَةً لِلْمَرِيضِ فَقَالَ " إِذَا مَاتَتْ فَآذِنُونِي " . فَمَاتَتْ لَيْلاً فَدَفَنُوهَا وَلَمْ يُعْلِمُوا النَّبِيَّ صلى الله عليه وسلم فَلَمَّا أَصْبَحَ سَأَلَ عَنْهَا فَقَالُوا كَرِهْنَا أَنْ نُوقِظَكَ يَا رَسُولَ اللَّهِ . فَأَتَى قَبْرَهَا فَصَلَّى عَلَيْهَا وَكَبَّرَ أَرْبَعًا .
It was narrated that Abu Umamah bin Sahi said:"A woman from among the people of Al-'Awali fell sick and the Prophet was the best in visiting the sick. He said: 'When she dies, inform me.' She died at night and they buried her without telling the Prophet. The following morning he asked about her and they said: we did not like to wake you, O Messenger of Allah.' So he went to her grave and offered the funeral prayer for her and said Takbir four times
Sahih · Abu Ghuddah
Sunan an-Nasa'i 1981 ·Book 21, Hadith 164·Also available on sunnah.com·